From 694b5a913d03fd7233edf6961c54edac78684519 Mon Sep 17 00:00:00 2001 From: Steve Sistare Date: Thu, 27 Mar 2025 07:52:10 -0700 Subject: [PATCH] migration: Avoid SNP guest crash due to duplicate cpr blocker With aux-ram-share=off, booting an SNP guest fails with: ../util/error.c:68: error_setv: Assertion `*errp == NULL' failed. This is because a CPR blocker for the guest_memfd ramblock is added twice, once in ram_block_add_cpr_blocker because aux-ram-share=off so rb->fd < 0, and once in ram_block_add for a specific guest_memfd blocker. To fix, add the guest_memfd blocker iff a generic one would not be added by ram_block_add_cpr_blocker. Fixes: 094a3dbc55df ("migration: ram block cpr blockers") Reported-by: Tom Lendacky Reported-by: Michael Roth Tested-by: Tom Lendacky Signed-off-by: Steve Sistare Message-ID: <1743087130-429075-1-git-send-email-steven.sistare@oracle.com> [reword subject line] Signed-off-by: Fabiano Rosas --- system/physmem.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/system/physmem.c b/system/physmem.c index e97de3ef65..333a5eb94d 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -158,6 +158,7 @@ static void io_mem_init(void); static void memory_map_init(void); static void tcg_log_global_after_sync(MemoryListener *listener); static void tcg_commit(MemoryListener *listener); +static bool ram_is_cpr_compatible(RAMBlock *rb); /** * CPUAddressSpace: all the information a CPU needs about an AddressSpace @@ -1908,13 +1909,18 @@ static void ram_block_add(RAMBlock *new_block, Error **errp) goto out_free; } - error_setg(&new_block->cpr_blocker, - "Memory region %s uses guest_memfd, " - "which is not supported with CPR.", - memory_region_name(new_block->mr)); - migrate_add_blocker_modes(&new_block->cpr_blocker, errp, - MIG_MODE_CPR_TRANSFER, - -1); + /* + * Add a specific guest_memfd blocker if a generic one would not be + * added by ram_block_add_cpr_blocker. + */ + if (ram_is_cpr_compatible(new_block)) { + error_setg(&new_block->cpr_blocker, + "Memory region %s uses guest_memfd, " + "which is not supported with CPR.", + memory_region_name(new_block->mr)); + migrate_add_blocker_modes(&new_block->cpr_blocker, errp, + MIG_MODE_CPR_TRANSFER, -1); + } } ram_size = (new_block->offset + new_block->max_length) >> TARGET_PAGE_BITS; -- 2.39.5